Subject: [PATCH v3 2/2] regulator: add device tree support for max8997

From: [email-masked] (Grant Likely)
Date: Mon, 12 Mar 2012 21:43:06 -0600

On Thu, 23 Feb 2012 18:08:08 +0530, Thomas Abraham <[email-masked]> wrote:
> Add device tree based discovery support for max8997.
> 
> Cc: MyungJoo Ham <[email-masked]>
> Cc: Rajendra Nayak <[email-masked]>
> Cc: Rob Herring <[email-masked]>
> Cc: Grant Likely <[email-masked]>
> Signed-off-by: Thomas Abraham <[email-masked]>
> ---
>  .../devicetree/bindings/regulator/max8997-pmic.txt |  134 +++++++++++++++++++
>  drivers/mfd/max8997.c                              |   72 ++++++++++-
>  drivers/regulator/max8997.c                        |  139 +++++++++++++++++++-
>  include/linux/mfd/max8997.h                        |    1 +
>  4 files changed, 344 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/regulator/max8997-pmic.txt
> 
> diff --git a/Documentation/devicetree/bindings/regulator/max8997-pmic.txt b/Documentation/devicetree/bindings/regulator/max8997-pmic.txt
> new file mode 100644
> index 0000000..d282635
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/regulator/max8997-pmic.txt
> @@ -0,0 +1,134 @@
> +* Maxim MAX8997 Voltage and Current Regulator
> +
> +The Maxim MAX8997 is a multi-function device which includes volatage and
> +current regulators, rtc, charger controller and other sub-blocks. It is
> +interfaced to the host controller using a i2c interface. Each sub-block is
> +addressed by the host system using different i2c slave address. This document
> +describes the bindings for 'pmic' sub-block of max8997.
> +
> +Required properties:
> +- compatible: Should be "maxim,max8997-pmic".
> +- reg: Specifies the i2c slave address of the pmic block. It should be 0x66.
> +
> +- max8997,pmic-buck1-dvs-voltage: A set of 8 voltage values in micro-volt (uV)
> +  units for buck1 when changing voltage using gpio dvs. Refer to [1] below
> +  for additional information.
> +
> +- max8997,pmic-buck2-dvs-voltage: A set of 8 voltage values in micro-volt (uV)
> +  units for buck2 when changing voltage using gpio dvs. Refer to [1] below
> +  for additional information.
> +
> +- max8997,pmic-buck5-dvs-voltage: A set of 8 voltage values in micro-volt (uV)
> +  units for buck5 when changing voltage using gpio dvs. Refer to [1] below
> +  for additional information.
> +
> +[1] If none of the 'max8997,pmic-buck[1/2/5]-uses-gpio-dvs' optional
> +    property is specified, the 'max8997,pmic-buck[1/2/5]-dvs-voltage'
> +    property should specify atleast one voltage level (which would be a
> +    safe operating voltage).
> +
> +    If either of the 'max8997,pmic-buck[1/2/5]-uses-gpio-dvs' optional
> +    property is specified, then all the eigth voltage values for the
> +    'max8997,pmic-buck[1/2/5]-dvs-voltage' should be specified.
> +
> +Optional properties:
> +- interrupt-parent: Specifies the phandle of the interrupt controller to which
> +  the interrupts from max8997 are delivered to.
> +- interrupts: Interrupt specifiers for two interrupt sources.
> +  - First interrupt specifier is for 'irq1' interrupt.
> +  - Second interrupt specifier is for 'alert' interrupt.
> +- max8997,pmic-buck1-uses-gpio-dvs: 'buck1' can be controlled by gpio dvs.
> +- max8997,pmic-buck2-uses-gpio-dvs: 'buck2' can be controlled by gpio dvs.
> +- max8997,pmic-buck5-uses-gpio-dvs: 'buck5' can be controlled by gpio dvs.
> +
> +Additional properties required if either of the optional properties are used:
> +- max8997,pmic-ignore-gpiodvs-side-effect: When GPIO-DVS mode is used for
> +  multiple bucks, changing the voltage value of one of the bucks may affect
> +  that of another buck, which is the side effect of the change (set_voltage).
> +  Use this property to ignore such side effects and change the voltage.
> +
> +- max8997,pmic-buck125-default-dvs-idx: Default voltage setting selected from
> +  the possible 8 options selectable by the dvs gpios. The value of this
> +  property should be between 0 and 7. If not specified or if out of range, the
> +  default value of this property is set to 0.
> +
> +- max8997,pmic-buck125-dvs-gpios: GPIO specifiers for three host gpio's used
> +  for dvs. The format of the gpio specifier depends in the gpio controller.
> +
> +
> +Regulators: The regulators of max8997 that have to be instantiated should be
> +included in a sub-node named 'regulators'. Regulator nodes included in this
> +sub-node should be of the format as below. Note: The 'n' in LDOn and BUCKn
> +represents the LDO or BUCK number as per the datasheet of max8997.
> +
> +    For LDO's:
> +		LDOn {
> +			standard regulator bindings here
> +		};
> +
> +    For BUCK's:
> +		BUCKn {
> +			standard regulator bindings here
> +		};
> +
> +The bindings inside the regulator nodes use the standard regulator bindings
> +which are documented elsewhere.
> +
> +Example:
> +
> +	max8997_pmic at 66 {
> +		compatible = "maxim,max8997-pmic";
> +		interrupt-parent = <&wakeup_eint>;
> +		reg = <0x66>;
> +		interrupts = <4 0>, <3 0>;
> +
> +		max8997,pmic-buck1-uses-gpio-dvs;
> +		max8997,pmic-buck2-uses-gpio-dvs;
> +		max8997,pmic-buck5-uses-gpio-dvs;
> +
> +		max8997,pmic-ignore-gpiodvs-side-effect;
> +		max8997,pmic-buck125-default-dvs-idx = <0>;
> +
> +		max8997,pmic-buck125-dvs-gpios = <&gpx0 0 1 0 0>, /* SET1 */
> +						 <&gpx0 1 1 0 0>, /* SET2 */
> +						 <&gpx0 2 1 0 0>; /* SET3 */
> +
> +		max8997,pmic-buck1-dvs-voltage = <1350000>, <1300000>,
> +						 <1250000>, <1200000>,
> +						 <1150000>, <1100000>,
> +						 <1000000>, <950000>;
> +
> +		max8997,pmic-buck2-dvs-voltage = <1100000>, <1100000>,
> +				    		 <1100000>, <1100000>,
> +						 <1000000>, <1000000>,
> +						 <1000000>, <1000000>;
> +
> +		max8997,pmic-buck5-dvs-voltage = <1200000>, <1200000>,
> +						 <1200000>, <1200000>,
> +						 <1200000>, <1200000>,
> +						 <1200000>, <1200000>;
> +
> +		regulators {
> +			ldo1_reg: LDO1 {
> +				regulator-name = "VDD_ABB_3.3V";
> +				regulator-min-microvolt = <3300000>;
> +				regulator-max-microvolt = <3300000>;
> +			};
> +
> +			ldo2_reg: LDO2 {
> +				regulator-name = "VDD_ALIVE_1.1V";
> +				regulator-min-microvolt = <1100000>;
> +				regulator-max-microvolt = <1100000>;
> +				regulator-always-on;
> +			};
> +
> +			buck1_reg: BUCK1 {
> +				regulator-name = "VDD_ARM_1.2V";
> +				regulator-min-microvolt = <950000>;
> +				regulator-max-microvolt = <1350000>;
> +				regulator-always-on;
> +				regulator-boot-on;
> +			};
> +		};
> +	};
> +

Good documentation

> diff --git a/drivers/mfd/max8997.c b/drivers/mfd/max8997.c
> index 20ecad3..13180be 100644
> --- a/drivers/mfd/max8997.c
> +++ b/drivers/mfd/max8997.c
> @@ -23,6 +23,7 @@
>  
>  #include <linux/slab.h>
>  #include <linux/i2c.h>
> +#include <linux/of_irq.h>
>  #include <linux/interrupt.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/module.h>
> @@ -123,6 +124,60 @@ int max8997_update_reg(struct i2c_client *i2c, u8 reg, u8 val, u8 mask)
>  }
>  EXPORT_SYMBOL_GPL(max8997_update_reg);
>  
> +#ifdef CONFIG_OF
> +/*
> + * Only the common platform data elements for max8997 are parsed here from the
> + * device tree. Other sub-modules of max8997 such as pmic, rtc and others have
> + * to parse their own platform data elements from device tree.
> + *
> + * The max8997 platform data structure is instantiated here and the drivers for
> + * the sub-modules need not instantiate another instance while parsing their
> + * platform data.
> + */
> +static int max8997_i2c_parse_dt_pdata(struct device *dev,
> +					struct max8997_platform_data **pdata)
> +{
> +	struct max8997_platform_data *pd;
> +
> +	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
> +	if (!pd) {
> +		dev_err(dev, "could not allocate memory for pdata\n");
> +		return -ENOMEM;
> +	}
> +
> +	pd->ono = irq_of_parse_and_map(dev->of_node, 1);
> +
> +	/*
> +	 * ToDo: the 'wakeup' member in the platform data is more of a linux
> +	 * specfic information. Hence, there is no binding for that yet and
> +	 * not parsed here.
> +	 */
> +
> +	*pdata = pd;
> +	return 0;
> +}
> +#else
> +static int max8997_i2c_parse_dt_pdata(struct device *dev,
> +					struct max8997_platform_data **pdata)
> +{
> +	return 0;
> +}
> +#endif
> +
> +static struct of_device_id __devinitdata max8997_pmic_dt_match[];

Move the actual definition of this structure up to here so that a forward
declaration becomes unnecessary.

> +static inline int max8997_i2c_get_driver_data(struct i2c_client *i2c,
> +						const struct i2c_device_id *id)
> +{
> +#ifdef CONFIG_OF
> +	if (i2c->dev.of_node) {
> +		const struct of_device_id *match;
> +		match = of_match_node(max8997_pmic_dt_match, i2c->dev.of_node);
> +		return (int)match->data;
> +	}
> +#endif
> +	return (int)id->driver_data;
> +}
> +
>  static int max8997_i2c_probe(struct i2c_client *i2c,
>  			    const struct i2c_device_id *id)
>  {
> @@ -137,9 +192,16 @@ static int max8997_i2c_probe(struct i2c_client *i2c,
>  	i2c_set_clientdata(i2c, max8997);
>  	max8997->dev = &i2c->dev;
>  	max8997->i2c = i2c;
> -	max8997->type = id->driver_data;
> +	max8997->type = max8997_i2c_get_driver_data(i2c, id);
>  	max8997->irq = i2c->irq;
>  
> +	if (max8997->dev->of_node) {
> +		ret = max8997_i2c_parse_dt_pdata(max8997->dev, &pdata);
> +		if (ret)
> +			goto err;
> +		i2c->dev.platform_data = pdata;

This line is illegal.  Drivers must *not* change the value of dev->platform_data.
instead the valid pdata pointer needs to be stored in the max8997 private data
structure.

> +	}
> +

If you tweak the definition of max8997_i2c_parse_dt_pdata() then this block can
be simplified to:

	pdata = max8997_i2c_parse_dt_pdata(max8997->dev, &pdata);
	if (!pdata) 
		pdata = i2c->dev.platform_data,
	if (!pdata)
		goto err;

Otherwise, the patch looks pretty good.  (although seeing the decode function
has got me thinking that we need a much better way of decoding the dt data).

g.

>  
> @@ -429,11 +491,19 @@ const struct dev_pm_ops max8997_pm = {
>  	.restore = max8997_restore,
>  };
>  
> +#ifdef CONFIG_OF
> +static struct of_device_id __devinitdata max8997_pmic_dt_match[] = {
> +	{ .compatible = "maxim,max8997-pmic", .data = TYPE_MAX8997 },
> +	{},
> +};
> +#endif
> +
>  static struct i2c_driver max8997_i2c_driver = {
>  	.driver = {
>  		   .name = "max8997",
>  		   .owner = THIS_MODULE,
>  		   .pm = &max8997_pm,
> +		   .of_match_table = of_match_ptr(max8997_pmic_dt_match),
>  	},
>  	.probe = max8997_i2c_probe,
>  	.remove = max8997_i2c_remove,
> diff --git a/drivers/regulator/max8997.c b/drivers/regulator/max8997.c
> index bb7cd9d..b31c4c9 100644
> --- a/drivers/regulator/max8997.c
> +++ b/drivers/regulator/max8997.c
> @@ -25,6 +25,7 @@
>  #include <linux/delay.h>
>  #include <linux/err.h>
>  #include <linux/gpio.h>
> +#include <linux/of_gpio.h>
>  #include <linux/slab.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> @@ -32,6 +33,7 @@
>  #include <linux/regulator/machine.h>
>  #include <linux/mfd/max8997.h>
>  #include <linux/mfd/max8997-private.h>
> +#include <linux/regulator/of_regulator.h>
>  
>  struct max8997_data {
>  	struct device *dev;
> @@ -958,6 +960,134 @@ static struct regulator_desc regulators[] = {
>  	},
>  };
>  
> +#ifdef CONFIG_OF
> +static int max8997_pmic_dt_parse_dvs_gpio(struct max8997_dev *iodev,
> +			struct max8997_platform_data *pdata,
> +			struct device_node *pmic_np)
> +{
> +	int i, gpio;
> +
> +	for (i = 0; i < 3; i++) {
> +		gpio = of_get_named_gpio(pmic_np,
> +					"max8997,pmic-buck125-dvs-gpios", i);
> +		if (!gpio_is_valid(gpio)) {
> +			dev_err(iodev->dev, "invalid gpio[%d]: %d\n", i, gpio);
> +			return -EINVAL;
> +		}
> +		pdata->buck125_gpios[i] = gpio;
> +	}
> +	return 0;
> +}
> +
> +static int max8997_pmic_dt_parse_pdata(struct max8997_dev *iodev,
> +					struct max8997_platform_data *pdata)
> +{
> +	struct device_node *pmic_np, *regulators_np, *reg_np;
> +	struct max8997_regulator_data *rdata;
> +	unsigned int i, dvs_voltage_nr = 1, ret;
> +
> +	pmic_np = iodev->dev->of_node;
> +	if (!pmic_np) {
> +		dev_err(iodev->dev, "could not find pmic sub-node\n");
> +		return -ENODEV;
> +	}
> +
> +	regulators_np = of_find_node_by_name(pmic_np, "regulators");
> +	if (!regulators_np) {
> +		dev_err(iodev->dev, "could not find regulators sub-node\n");
> +		return -EINVAL;
> +	}
> +
> +	/* count the number of regulators to be supported in pmic */
> +	pdata->num_regulators = 0;
> +	for_each_child_of_node(regulators_np, reg_np)
> +		pdata->num_regulators++;
> +
> +	rdata = devm_kzalloc(iodev->dev, sizeof(*rdata) *
> +				pdata->num_regulators, GFP_KERNEL);
> +	if (!rdata) {
> +		dev_err(iodev->dev, "could not allocate memory for "
> +						"regulator data\n");
> +		return -ENOMEM;
> +	}
> +
> +	pdata->regulators = rdata;
> +	for_each_child_of_node(regulators_np, reg_np) {
> +		for (i = 0; i < ARRAY_SIZE(regulators); i++)
> +			if (!of_node_cmp(reg_np->name, regulators[i].name))
> +				break;
> +		rdata->id = i;
> +		rdata->initdata = of_get_regulator_init_data(
> +						iodev->dev, reg_np);
> +		rdata->reg_node = reg_np;
> +		rdata++;
> +	}
> +
> +	if (of_get_property(pmic_np, "max8997,pmic-buck1-uses-gpio-dvs", NULL))
> +		pdata->buck1_gpiodvs = true;
> +
> +	if (of_get_property(pmic_np, "max8997,pmic-buck2-uses-gpio-dvs", NULL))
> +		pdata->buck2_gpiodvs = true;
> +
> +	if (of_get_property(pmic_np, "max8997,pmic-buck5-uses-gpio-dvs", NULL))
> +		pdata->buck5_gpiodvs = true;
> +
> +	if (pdata->buck1_gpiodvs || pdata->buck2_gpiodvs ||
> +						pdata->buck5_gpiodvs) {
> +		ret = max8997_pmic_dt_parse_dvs_gpio(iodev, pdata, pmic_np);
> +		if (ret)
> +			return -EINVAL;
> +
> +		if (of_property_read_u32(pmic_np,
> +				"max8997,pmic-buck125-default-dvs-idx",
> +				&pdata->buck125_default_idx)) {
> +			pdata->buck125_default_idx = 0;
> +		} else {
> +			if (pdata->buck125_default_idx >= 8) {
> +				pdata->buck125_default_idx = 0;
> +				dev_info(iodev->dev, "invalid value for "
> +				"default dvs index, using 0 instead\n");
> +			}
> +		}
> +
> +		if (of_get_property(pmic_np,
> +			"max8997,pmic-ignore-gpiodvs-side-effect", NULL))
> +			pdata->ignore_gpiodvs_side_effect = true;
> +
> +		dvs_voltage_nr = 8;
> +	}
> +
> +	if (of_property_read_u32_array(pmic_np,
> +				"max8997,pmic-buck1-dvs-voltage",
> +				pdata->buck1_voltage, dvs_voltage_nr)) {
> +		dev_err(iodev->dev, "buck1 voltages not specified\n");
> +		return -EINVAL;
> +	}
> +
> +	if (of_property_read_u32_array(pmic_np,
> +				"max8997,pmic-buck2-dvs-voltage",
> +				pdata->buck2_voltage, dvs_voltage_nr)) {
> +		dev_err(iodev->dev, "buck2 voltages not specified\n");
> +		return -EINVAL;
> +	}
> +
> +	if (of_property_read_u32_array(pmic_np,
> +				"max8997,pmic-buck5-dvs-voltage",
> +				pdata->buck5_voltage, dvs_voltage_nr)) {
> +		dev_err(iodev->dev, "buck5 voltages not specified\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +#else
> +static int max8997_pmic_dt_parse_pdata(struct max8997_dev *iodev,
> +					struct max8997_platform_data *pdata)
> +{
> +	return 0;
> +}
> +#endif /* CONFIG_OF */
> +
>  static __devinit int max8997_pmic_probe(struct platform_device *pdev)
>  {
>  	struct max8997_dev *iodev = dev_get_drvdata(pdev->dev.parent);
> @@ -968,6 +1098,12 @@ static __devinit int max8997_pmic_probe(struct platform_device *pdev)
>  	int i, ret, size;
>  	u8 max_buck1 = 0, max_buck2 = 0, max_buck5 = 0;
>  
> +	if (iodev->dev->of_node) {
> +		ret = max8997_pmic_dt_parse_pdata(iodev, pdata);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	if (!pdata) {
>  		dev_err(pdev->dev.parent, "No platform init data supplied.\n");
>  		return -ENODEV;
> @@ -1146,7 +1282,8 @@ static __devinit int max8997_pmic_probe(struct platform_device *pdev)
>  			regulators[id].n_voltages = 16;
>  
>  		rdev[i] = regulator_register(&regulators[id], max8997->dev,
> -				pdata->regulators[i].initdata, max8997, NULL);
> +				pdata->regulators[i].initdata, max8997,
> +				pdata->regulators[i].reg_node);
>  		if (IS_ERR(rdev[i])) {
>  			ret = PTR_ERR(rdev[i]);
>  			dev_err(max8997->dev, "regulator init failed for %d\n",
> diff --git a/include/linux/mfd/max8997.h b/include/linux/mfd/max8997.h
> index 818486c..ba92375 100644
> --- a/include/linux/mfd/max8997.h
> +++ b/include/linux/mfd/max8997.h
> @@ -75,6 +75,7 @@ enum max8998_regulators {
>  struct max8997_regulator_data {
>  	int id;
>  	struct regulator_init_data *initdata;
> +	struct device_node *reg_node;
>  };
>  
>  enum max8997_muic_usb_type {
> -- 
> 1.6.6.rc2
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies,Ltd.